<!DOCTYPE HTML>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<title>无标题文档</title>
<style>
.box{width:400px;height:400px;margin:50px auto; transition:5s linear;}
.box div{width:180px;height:180px;margin:10px;border:1px solid #000; box-sizing:border-box;float:left;background:url(img/new_bg.png) no-repeat;}
.box div:nth-child(1),.box div:nth-child(4){ border-radius:0 70%;}
.box div:nth-child(2),.box div:nth-child(3){ border-radius:70% 0;}
.box:hover{ -webkit-transform:rotate(720deg);}
</style>
</head>
<body>
<div class="box">
	<div></div>
    <div></div>
    <div></div>
    <div></div>
</div>
</body>
</html>
